df.loc[df['mID']=='A','hID'].agg(['nunique','count','size'])
words = ['a', 'b', 'c', 'a'] unique_words = set(words) # == set(['a', 'b', 'c']) unique_word_count = len(unique_words) # == 3
aa="XXYYYSBAA" bb=dict(zip(list(aa),[list(aa).count(i) for i in list(aa)])) print(bb) # output: # {'X': 2, 'Y': 3, 'S': 1, 'B': 1, 'A': 2}